mep803 goes to full overload on start up

[George1953]

I recently went to Ka pick up an mep803a spent 400 on it getting it running. Soon as it starts it goes to overload with no voltage showing Anyone have any ideas Thanks

 

[Digger556]

The Overload fault light is coming on? This could be a false trip or a serious short.

1. Does the engine sound like its being loaded down immediately? It is throwing black smoke beyond the normal puff on startup?

2. Does this unit have the quad fuse mod? Or MOV mod?

3. How well to you understand the basic functions of these units? Have you read through the TMs yet?


Give us some more details, then we can help get you pointed in the right direction.

 

[George1953]

The Overload fault light is coming on? This could be a false trip or a serious short.

1. Does the engine sound like its being loaded down immediately? It is throwing black smoke beyond the normal puff on startup?

2. Does this unit have the quad fuse mod? Or MOV mod?

3. How well to you understand the basic functions of these units? Have you read through the TMs yet?


Give us some more details, then we can help get you pointed in the right direction.

I

 

[Light in the Dark]

Internal contact corrosion can cause this issue, as can defective burden resistors. Digger asked some good questions to get a baseline.

 

[George1953]

I

The Overload fault light is coming on? This could be a false trip or a serious short.

1. Does the engine sound like its being loaded down immediately? It is throwing black smoke beyond the normal puff on startup?

2. Does this unit have the quad fuse mod? Or MOV mod?

3. How well to you understand the basic functions of these units? Have you read through the TMs yet?


Give us some more details, then we can help get you pointed in the right direction.

i

 

[George1953]

I just got this 803 unit spent 400 by the time i got batteries,filters and fluids first time firing it was max load barely run no indicated on the voltage meter or frcquency meter either meter said 4 hrs since it was in the shop. when i got it fired up water leaking out of the thermostat housing.some butt head took it out and left it with a gasket half in too. no thermostat got 4000 tied up in this need some help

 

[George1953]

soon as you start it it loads max sometimes 25 percent 40 hrs since shopped in Oragon. Somethin isnt right

 

[George1953]

It loads up soon as you start the engine barely running

 

[CallMeColt]

Sounds like you have a short. Be careful. Probably why it was sent to surplus. If that is the case, it could have cause some issues with everything else as far as controls goes. I'd start by completely disconnecting the main lines coming from the generator and go from there.

 

[Guyfang]

Soon as it starts it goes to overload with no voltage showing.

Please describe this better. Goes to overload. What happens when it goes to overload? The Idiot light comes? Engine bogs down? Smoke? Better description. A video would be better.

Where did you measure voltage? At the 120 volt outlet? At the load terminals? Did you turn on the S5, (AC Interupter Switch) after it started running?

 

[Guyfang]

You started a thread on this generator set before. Why are you not posting there? Its hard to keep it all straight. Or is this a different gen set?

 

[Digger556]

That sounds like there is an actual short circuit.

Since it happens immediately, I'm assuming, for now, that your main contactor is not energized, also, because you are indicating load on the meter, the problem is likely downstream of the current transformers (CTs).

No matter what, you need to stop firing up the engine until you can track down the issue. I would start by pulling the top cover and inspecting all the wiring between the genhead's terminal block and the final output wires. Mice love that area of the generator.

 

[George1953]

Soon as it starts it goes to overload with no voltage showing.

Please describe this better. Goes to overload. What happens when it goes to overload? The Idiot light comes? Engine bogs down? Smoke? Better description. A video would be better.

Where did you measure voltage? At the 120 volt outlet? At the load terminals? Did you turn on the S5, (AC Interupter Switch) after it started running?

Yes as soon as i start the unit it goes to full load and puts a heavy load on the engine . No voltage on the meters and i did flip the ac interuptor

 

[Ray70]

One thing to check on the 802 / 803 is to take off the top cover and look carefully at the 12 leads coming off the generator going up to the terminal strip and to the AC select switch as well as the 3 fatter wires going from the AC select switch into the circuit interruptor.
Make sure none of the wires have gotten chaffed at all from rubbing on the sheet metal.
This has been reported a few times on Tier2 sets with poorly dressed wiring.

 

[Guyfang]

Yes as soon as i start the unit it goes to full load and puts a heavy load on the engine . No voltage on the meters and i did flip the ac interrupter.

Lets try this again.

You started the gen set.
It runs normal.
You flipped up the S5, and it goes to full load, and bogs the engine down.

Just like that? Because the way you just described it:

You started the set
It went to full load, and bogs the engine down
Then you flipped up S5.

And this makes no sense to me.

What I am asking you is, if you started the set, and right then and there, without you doing anything else, it went to full load? Just like that?

By flip the Interrupter, (S5) are you telling me you flipped in on, off? Its important to know what you did and when. If the set goes to an overload, with out you turning the S5 on, then the problem is before the K1, (Output contactor) or the K1 is closed, (Shorted?) Read and do Rays post #14.